Verified CarBotCon example sketch and fixed program hang in library (debug SerialUSB printout would cause lib to hang when not connected to an active terminal program).  Should check other combinations of vel and rad inputs to make sure it really is working as expected.  Next is verify pypose.ino interaction with PyPose on a PC.
Idiot.  Used expanded status COMM_* values from dxl_devices instead of standard COMM_* from dxl_constants.
CarBotCon appears to work as expected with additional vel and rad values.
PyPose seems to work, but requres "set" to be clicked twice to actually set the new position.  No problems if using "live update" of servo positions.  No trouble reading either.